Fluid pressure intensifying device



y 1950 v o. J. SAARI 2,508,298

FLUID PRESSURE INTENSIFYING DEVICE Filed April 16, 1948 Stream PatentedMay 16, 1950 UNITED STATES PATENT OFFICE FLUID PRESSURE INTENSIFYINGDEVICE Oliver '3. Sand, Bronx, N. Y. Application April 16,1948,1SerialNo. 21537 Claims. 1

This invention relates to a hydraulic pressure intensifier, and moreparticularly to a device for boosting the pressure in a hydraulic fluidline to give a smooth uninterrupted flow without the aidoi additionalpumps or motors.

The booster of the invention is easily installed in the pressure line ofa .pump, and by increasing the pressure permits the use of smaller ramdiameters,.faster advance .and return speeds, and continuous highpressure for holding, deep drawing, etc. The device may be mounted inany posithan without altering its effectiveness.

.Further advantages of the booster are that it may he. used with largevolume pumps, and can be used with either variable or constant deliverypumps. The device contains no bearings or packings. to service, andneeds no adjustments. ;By its design, thebooster may be produced at lowcost and maintained in service over long periods withno maintenancecost.

An object of the invention is. to provide a hydraulic pressureintensifier having the above advantages.

, Another object of the invention is to provide a booster including apair of interlockedand selfsynchronizing pistons so arranged as toprovide delivery of intensified oil pressure at all times.

' These and other objects of the invention will be apparent from thefollowing specification and the accompanying drawing, in which thefigure .piston 11,. and similar grooves Ma .and I4?) are provided nearthe ends of piston I2. Each piston has piston rods [5, l6 and l1, 18.extending from each of its ends and extending into cylinders l5a, |6a,Ila. and la, respectively, these cylinders being of less diameter thancylinders Ma and Ho, and being in communication with the largercylinders through reduced cylinder portions 20 which are dimensioned toprovide for movement of the piston rods but at the same time to seal ofithe large cylinder portions Ha, 1.2a from the smaller cylinder portions|5a lta, etc. Cylinder |5a is connected at its closed end with cylinderIla by a passage 22 containing. two checkvalves 23,, 24 opening onlytoward each other A conduit .25 .for the, intensified pressure fluid is.connected to conduit 22 at a point between check valves '23, 24

2 closed ends by a conduit 21 and check valves 28 and corresponding inposition and direction of opening to those connecting cylinders "la andMa. Conduit 21 also communicates with intenslfled pressure. conduit 25at a point between check valves .28, 29.

Conduits 22 and '21 are connected to and paralleled along most of theirlengths by conduits 30, 3|, respectively, each containing a pair of oneway check valves 32, 33 and 34, spaced in a manner similar to the checkvalves 23, 24 and '28,, 29, but operating oppositely to the latter, thatis, check valves '32 and 33 permit flow of fluid only toward cylinders|5a and Ila, respectively. Check valves 34 and 35permit flow only towardcylinders IEa and Ma, respectively. Conduits 30 and 3| are bothconnected at points located between their check valves with a conduit3-! which receives fluid being fed to the device by a pump or otherpressure source (not shown).

Passages and 4| provide communicationbetween the ends of cylinders Hoand the corresponding ends of cylinder |2a, and these two passages bothconnect with fluid supply passage 31. Conduits 40 and 41 are connectedto and paralleled along most of their lengths by passages 42 and 43,respectively, the two latter ,pas-

Cylinders vIlia and 18a are connected-at their 56 sages being connectedwith a drain conduit 44 which leads, for example, back to the fluidsupply tank (not shown).

Conduits 4|], 4|, 42, and 43 communicate with cylinders 5| and 52 whichcontain movable pistons 53 and 54,, respectively. The openings ofpassages 40,, 4|, 42 and 43 into cylinders 5| and 52 are spaced alongthe lengths oi these cylinders and each of the pistons 53, 54 has fouropenings so positioned that piston 53 While blocking passages 4'0 and43, permits flow through passages 4| and 42. In the other position ofpiston 53, it permits fluid flow through passages 40 and 43 and blockspassages 4| and 42. Piston 54 is similarly constructed and operable,except that, as will be explained presently, piston 54 operates out ofphase with piston 53.

The right. end of cylinder 5| is connected by a passage 56 with theinterior of cylinder Ila near its mid point, and the left end ofcylinder 5| is connected by a passage 51 with the left end of cylinder|2a at a point located a short distance from the left end of cylinderI211. The

opening of passage '55 into cylinder '||a is so positioned that theright hand end of piston. gmoves clear of the opening when thepistonmoves to its extreme left hand position. The left end or cylinder52 is connected by a passage 58 with der that groove |4a will connectpassage 59 to drain at 60 when piston I2 is in its extreme right handposition, while groove I 4b will conhect passage 58 to drain at 60 whenpiston I2 is in its extreme left hand position.

in the case of cylinder Ila, it has-a connection to drain at 6| sopositioned that grooveIB will connect passage 56 to drain at 6| whenpiston II is in its extreme right hand position.

In the phase of operation shown in the drawing, the pressure from thepump (not shown) entering conduit 31 passes through check valve '34 andat the same time through passage 4|,

thus applying pressure to the end of piston rod I6 and to the right endof piston II, causing movement of piston II to the left. The pressure"from the pump also passes downwardly through port 40 into the left endof cylinder I 2a, and at the same time passes through port 30 to opencheck valve 33 and pass into cylinder I2a which also assists in movingpiston rod I1 and piston I2 to the right in the drawing. Access ofpressure fluid to the left surface of piston II is prevented by piston53 so that the pressure on combined areas of piston I 6 and the rightend of piston II overcomes pressure tending to open valve 32, thusmaintaining this valve closed and forcing piston II and piston rod I tothe left v and opening valve 23.

' The pressure in the left end of cylinder I2a passes through conduit 51as soon as piston I2 has moved far enough to the right to uncover theopening of passage 51 into cylinder I2a so I that the pressure withincylinder I2a passing through conduit 51 passes into the left end ofcylinder 5| to move piston 53 to its right-hand position as shown and tomaintain it in this position. As long as piston 53 is in its righthandposition as shown, it connects the left end of cylinder Ila. through theupper portion of conduit 40 and the upper portion of conduit 42 with theconduit 44 which passes to drain, thus permitting movement of piston IIto the left. The fluid in cylinder-I5a passes through check valve 23,forcing this valve open, and then passes through conduit 25 which is theconduit for the fluid under intensified pressure. Check valve 24prevents passage of the fluid from cylinder I5a into cylinder-Ila. Itwill be apparent that the pressure of the fluid passing from cylinderI5a to conduit 25 is intensified due to the fact that the pressure onthe surfaces of piston II and piston rod I6 is concentrated on fluid incontact with piston rod I5, the left end of cylinder Ila I beingconnected to drain.

The movement of piston I2 to the right under the pressure of the fluidpassing through the lower portion of conduit 40 and through the lowerportion of conduit 30 past check valve 33 causes an increase in thepressure in cylinder I8a since the right end of cylinder I2a is coninected to drain, and the fluid in cylinder I8a. is .forced past checkvalve 29 into the intensified pressure conduit 25, check valve 28'preventing movement of this fluid through passage 3|. The fluidentrapped within the right-hand end of cylinder |2a during the movementof piston I2 to the right escapes through conduit 43 to the conduit 44which connects to the drain.

As piston I2 moves to the right, it exposes first the opening of conduit51 into cylinder I211 to shift piston 53 to the right as describedabove, and thereafter with further movement of piston I2 to the right,exposes the opening of conduit 58 into cylinder I2a, thereby permittingthe incoming fluid pressure from passage 31 to pass from cylinder I2athrough conduit 58 to the lefthand end of cylinder 52 so as to urgepiston 54 to the right. This movement of piston 54 to the right cannottake place, however, until piston I2 reaches its extreme right-handposition, in which it is shown in the drawing, where it connects theright-hand end of cylinder 52 through conduit 59 and groove 14a inpiston I2 to drain through passage 55. When the pressure within theright-hand end of cylinder 52 is thus re leased, the piston 54 is freeto move to the right from the position in which it is shown in thedrawing. In the right-hand position of piston 54, conduit 40 is blocked,conduit 42 is open, conduit 43 is closed, and conduit 4| is open.

Movement of piston 54 to its right-hand position closes on the flow offluid from the pump to cylinder IZa through conduits 31 and 40 due tothe fact that it blocks conduit 40, but at the same time, it connectsthe left-hand end of cylinder IEa through conduit 42 to the drainconduit 44. In its right-hand position, piston 54 also connects theright-hand end of cylinder I2a to the incoming fluid pressure conduit 31since it opens conduit 4| and blocks the connection 43 of the right-handend of cylinder I20. with drain conduit 44. The fluid pressure enteringthrough conduit 3! then forces open check valve 35 so as to pass intothe right-hand end of cylinder I8a, while at the same time the fluidpressure from conduit 3! enters the right-hand end of cylinder I2athrough conduit 4|. The combined pressures on the right-hand ends ofpiston I2 and piston rod I8, and the connecting of the left-hand end ofcylinder I 2a through conduit 42 to drain permits the pressure fromconduit 31 to force the piston I2 to the left so as to place the fluidwithin cylinder I'Ia, under intensified pressure, and to force thisfluid past check valve 24 into the intensified pressure conduit 25.Check valve 23 prevents the intensified fluid pressure from passingthrough the upper part of passage 22 into cylinder I5a.

When piston II completes its leftward movement it exposes the opening ofconduit 56 into the interior of cylinder I la. and permits pressure fromconduit 31 through conduit 4| to pass from the interior of cylinder I lainto conduit 56 and thence into the right-hand end of cylinder 5| tourge piston 53 to its left-hand position in which it closes conduit 4|,opens conduit 43, closes conduit 42, and opens conduit 40. This leftwardmovement of piston 53 occurs at the time when conduit" 51 is connectedthrough the left end of cylinder IZa and through conduit 42communication with the incoming pressure :con-

duit 31. "The closing of conduit 42 disconnects "drain conduit 44.

no: end of cylinder, 11o from communication with the drain conduit 44,while the opening of conduit 40 permits fluid pressure fromlconduitvi'l'fto enter the left end of cylinder Ha. The

duit'through passage #3 and pressure from pump conduit 31' ispassing'into' "both cylinderjfla and the left end of cylinder 'ilu,piston H is therefore forced to move to the right and the fluidentrapped within cylinder ifia is forced past check valve 18 underintensified pressure into the intensiiied pressure conduit 25, meanwhileholding valve '34 closed.

I Returning now to piston 12, the leftward moveinent of piston l2'after'mcvementof piston to .the right "finaliy brings groove Hi1 into aposition to connect conduit 58. with drain "conduit 60, and at the sametime to expose the connection of conduit 5.9 with the right-end ofcylinder 12w seas to permit the pressure from-conduits 3'! and 4| withinthe righthand end of cylinder 12a: to pass a through conduit 59 into therigh'thand end of cylinder 52 so as to urge piston 54 toits leithandposition, the fluid under pressure inthe lefthanci end of cylinder 52escaping through conduit 58.

- along groove 1th, and out of drain conduit 60. "With this occurrence,the'iefthand end'oi cylinder 12a is again connected with the pumppressure conduit 31 and the righthand end (if-cylinder "12a is connectedthrough conduit 43 with the movement to the right under the pressure offluidfrom conduit 31 passing'through conduit 40 into the left end ofcylinder Ha. The en- "trapped within cylinder 18a is forced past checkvalve 29 under intensified pressure into conduit As piston 12 moves tothe right it first-passes "the opening of conduit 51 into cylinder m and"til piston H has reached its extreme position 0f "movement to the rightin which it connects condu'it 58 through groove 13 with the drainconduit ii, so as to relieve pressure Withinfhdfighfliaald end of"cylinder 51. The movement of "piston so to the right then permitspressure from conduit 51 to pass into the right 'en'dloi cylinder 1 la,and.

permits fluid in the left end oicylinder ita to passput' through the"upper portions of conduitifl and '42 to the drain conduit 34. The.iiuid entrapped within cylinder $541, "is placed underincreasedpressure and forced past check valve 23 into intensifiedpressure conduit 25.

. It will thus be clear from the above description thatthe mode ofoperation described continues over and over again-as long as thepressure is sup- "plied to conduit 31.

With respeott'o the relative positioning-oi drain duct 60 and theopenings offl'uctsfid and 59 into cylinder I'Za, the positioning is suchthat when piston I2 is in its extreme righthand position,

duct 59 "is oonn'ected't'o duct to andthe left end of piston l2 exposesopening, of conduit into-cylinder-flu. When piston i2 isinits extremelefthandposition, conduit 58 is in communication by means of groove hitwith drain duct Eli and the 'righthand endofpis'ton '12 exposes'the'openinpof Piston 42 then starts the duct 5! into cylinder m so asto permiticomn unicati-on between duct 59 and the lower end of conduit4'1. When the piston l2 isin its extreme lefthand position, the-re is,however, no communication between conduit 59 and drain duct 60.

With respect to the positioning of drain duct 6! and the opening ofconduit 56 into cylinder l la, the drain duct-til is oifset to the leftout of line with the opening into conduit 56 so that when piston 11 isin its extreme lefthand positionthe drain conduit 6| is closed andconduit 5611s in communication through the interior of cylinder 11 awith the upper end of conduit 41. When the piston H is in its extremerightharnd position,.the opening-of duct: 56 into the interior ofcylinder 1 i commnnicateswlth groove 13 which also commun-icaiiesv withdrain conduit .64

Itwillhe apparent that thespeed of the pistons 1 Landvl-Z. isv governedby the capacity'of the pump supplying fluid to conduit 31, so that thegreater the volume of fluid supply, the greater the speed of thepistons. The spring pressed ball check valves .23, 24,, 28, and 2.9reduce the pulsation at the stroke reversing intervals to an absoluteminimum by preventing. any momentary backflow of the intensifiedpressure011.

One or more spring loaded detents 10. are used with each of the twopiston valves 53 and 54 so as to retain these piston valves in .each oftheir two positions except when the pressure in one or the other. endsof the cylinders 5|, 521s. suilicient to move the respective piston toits other position. These detents also serve the function of holding thevalve pistons 53, 54 in their respective positions regardless of theorientation of the mounting of the pressure intensifier itself. Thedetents could of course be located in the housing or body Iii tocooperate with depressions in thepistons 53, 5'4. Suitable projections(not shown) on the ends of valve pistons 53 and 54 may be, provided tolimit their movement in each direction.

. It should also be apparent that the amount "of intensificationpf thepressure is a function of-the diii'erential-ratio between the surfaceof'the ends of pistons H and i2 and the surface of the surface area ofthe ends of each of the piston rods 15, "Hi, H, Hi. The volumetricoutput of the hydraulic intensifier is of course inversely proportionalto the pressure ratio so that, for example,

if the pressure is doubled, the volumetric output is ha lvedporii' thepressure is tripled, the volumetric output d'ecrea'ses to athird of theoriginal intensified pressure could be replaced :by other types ofsimilarly operatmg. check "valves. The

- shape of the main pistons could also be'varied :so

long as each piston has at least two separate fluid pressure areas oneach \endso that the separate areas on thexslde of a piston in thedirection of movement of the piston can be connected one to theintensified pressure outlet and one torlrain. ilhetannularigroovesia'hout eachinrain piston could he replaced "by passages through thepiston, although this might necessitate maintaining the pistons againstrotation.

The form of the invention which 12 have :de-

scribed is but a preferred embodiment, and is not to be considered aslimiting the invention to the specific embodiment shown. It ismyintention to cover by my patent all variations of the inventionfallingwithin the scope oi. the claims and outside the prior art.

' areas, second conduit means for connecting one fluid contact area ofeach side of each piston to said drain outlet, valve means controllingsaid second conduit means and at least some of said first conduit means,said valve means having positions'for completing the connection of saidfluid supply inlet to both areas of one side of each piston to move saidpiston in a direction away from'that side, while blocking one area ofeach of the other piston sides from communication with said inlet andconnecting said blocked area with said drain outlet, third conduit meansconnecting the remaining side of each piston with said intensifiedpressure outlet, and connection reversing means operable by said pistonsto shift said valve means to reverse said connections as said pistonsapproach the limits of their movement in each direction, therebyreversing the direction of movement of said pistons, said valve meanscomprising two fluid operated valves, each having two positions, firstand second cylinders in which said pistons reciprocate, connections todrain positioned in the side wall of each cylinder, said pistons havingpassages which communicate with one of said drain connections during aportion of the piston movement, said connection reversing meansincluding first and second valve operating fluid passageways connectingthe first valve with both end portions of the first cylinder and thirdand fourth valve operating fiuid pas sageways connecting the secondvalve with one end portion of each cylinder, the proportioningof saidpistons, the positioning of said passages and the positioning of theopenings of.said passageways into said cylinders being so related thatin ;one extreme position of movement-of; saidfirst 1 piston, the firstof the passageways to said first valve is connected to a drainconnection by a passage "in said piston while the second passageway tosaid first valve isin communication through a first end of said cylinderwith the piston moving-fluid from said inlet, said first piston in itsopposite extreme position putting said first passageway intocommunication wth the other end of said first cylinder for receivingfluid therefrom and putting said second passageway in communication witha drain connection through a passage in said first piston, said secondpiston in one extreme position of movement connecting said-thirdpassageway with a drain connection and in its other extreme positionputting said third passageway in communication with one end of saidcylinder to receive fluid therefrom,'said fourth passageway beingconnected to said first cylinder at a point positioned between the endof the cylinder andthe opening of the second passageway into thecylinder to receive fiuid from that end of the cylinder during the majorportion of the movement of said first piston in both directions.

-2. A device as set forth in claim 1,.saidv fluid operated valves beingpistonvalves, valve cylinders in which said valve pistons reciprocate,said first and second passageways being connected to opposite ends ofthe cylinder of said first piston valve, and said third and fourth'passageways being connected to opposite ends of the cylinder of saidsecond valve. I f

3. A fluid pressure intensifying device comprising a fluid supply inlet,an outlet for fluid under intensified pressure, an outlet to drain, apair of main cylindershaving enlarged central portions and reduced endportions, a piston reciprocably mounted in each cylinder, each pistonhaving an enlarged central portion and a reduced end portion slidable inthe corresponding cylinder portions, first and second conduitsconnecting one reduced end portion of one cylinder with a reduced endportion of the othercylinder, third and fourth conduits connecting theother reduced end portions of the two cylinders, a pair of spaced checkvalves in each of said first and fourth conduits, each check valveopening only toward the other check valve in the same 'conduit,'saidcheck valves permitting fiow only in a direction away from the reducedcylinder portions to which said first and fourth conduits connect, apair of spaced check valves in each of said second and third conduits,each of said last mentioned check valves opening only away from theothercheck valve in the same conduit, said last mentioned check valvespermitting flow only in a direction toward the reduced cylinder portionsto which said second and third conduits connect, a connection from saidfluid supply inlet to said second and third conduits at points locatedbetween the check valves in each conduit, a connection from saidintensified pressure outlet to said first and fourth conduits at pointslocated between the. check valves in each conduit, fifth and sixthconduits paralleling said first and second conduits and connecting theends of the enlarged portions of the two cylinders which correspond tothe reduced ends connected by the first. and second conduits, seventhand eighth conduits similarly connectin the other ends of the enlargedcylinder portions, first and second valve cylinders each intersectingsaid fifth, sixth, seventh and eighth conduits at spaced positions, afirst connection from one end of the first valve cylinder to theinterior of the enlarged portion of the first main cylinder at a pointlocated on one side of the center of the cylinder-so asto be uncoveredby the piston in that cylinder during the final portion of the movementOfthat piston toward the end of the cylinder farther removed from saidconnection, a second connection from the other end ofsaid first valvecylinder to the interior of the enlarged portion of said first maincylinder at a point positioned similarly to said first connection but onthe opposite side of the mid point of said cylinder, a third connectionfrom one end of the second valve cylinder to the interior of theenlarged portion of said first main cylinderat a point spaced betweensaid second connection and the endof the main cylinder nearer the secondconnection, a fourth connection between the other end of said secondvalve cylinder and the interior of the en larged portion of the secondmain cylinder at a point positioned to one side of the mid pointloi thecylinder so to be uncovered by the piston, in

said cylinder-during the final portion of its movement toward the endofthe. cylinder farther removed from saidjourth connection, means ,carriedby said first piston for connecting said first connection to drain atone end piston position and for connecting the second connection todrain in its other end position, means carried by said second piston forconnecting said fourth connection to drain when said second piston is inits end position of movement in the direction of the end of the cylindernearer said connection, a connection from said fluid supply inlet tosaid fifth and eighth conduits at points located between theintersections of said conduits with said valve cylinders, a connectionto drain communicating with said sixth and seventh conduits at pointslocated between the intersections of said conduits and said valvecylinders, and a valve piston in each of said valve cylinders, each ofsaid valve pistons having two positions and having ports located so thateach piston blocks said first and third conduits and completes saidsecond and fourth conduits in one position, and blocks said second andfourth conduits and completes said first and third conduits in the otherposition.

i6 4. A fluid pressure intensifying device as set forth in claim 3, saidmeans carried by said main pistons comprising annular grooves about theperipheries of said pistons.

5. A fluid pressure intensifying device as set forth in claim 3, andspring pressed detent means yieldably retaining said valve pistons ineach of their positions.

OLIVER J. SAARI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,274,224 Vickers Feb. 24, 19422,293,076 Pointing Aug. 18, 1942 2,336,446 Tucker et al. Dec. 7, 19432,442,916 Buchanan June 8, 1948

